1. Field of the Invention
This invention relates to fiber cables, and in particular to an apparatus and method to protect fiber ribbons.
2. Background of the Invention
Fiber cable was invented in the early 1970s, and its use has grown to include telecommunications, medicine, military, automotive, and industrial. Telecommunications applications include global networks, local telephone exchanges, subscribers' homes, and desktop computers, and carry voice, data, or video over distances of ranging from a few feet to hundreds of miles.
Optical fiber is frequently used for transmission of data signals in private networks, such as exist in manufacturing firms, banks, universities, financial firms, and more. These entities have a need for secure, reliable systems to transfer computer and monetary information between buildings to the desktop terminal or computer, and around the world. The security inherent in optical fiber systems is a major benefit. Cable television or community antenna television (CATV) companies find the high information-carrying capacity, or bandwidth, of fiber cable extremely useful in transmitting signals to subscribers.
Intelligent transportation systems also find great utility in fiber cable. Examples of these include smart highways with intelligent traffic lights, automated toll booths, and changeable message signs to give motorists information about delays and emergencies.
Fiber cables routinely carry hundreds of individual fibers. These fibers are grouped into discreet bundles called ribbons. For example, a single fiber cable may carry between 216 and 864 individual fibers. These individual fibers are typically grouped into a number of ribbons, for example, twelve ribbons. Strengthening members are also included in the fiber cable assembly, to provide the strength and stiffness necessary to protect the fibers from stretching and excessive bending.
A critical point in fiber cable systems is the location where a fiber cable containing a plurality of ribbons is split up into its component ribbons. Just as the strengthening members protect the individual fibers along the run of the fiber cable, a router is recommended to protect the individual ribbons once these emerge from the protection of the cable sheathing and strengthening members.
Thus, it would be desirable to provide an apparatus and method to protect fiber ribbons at the point where they emerge from the protection of the fiber cable.
Existing Designs
A number of designs have been proposed to support fiber ribbons exiting their fiber cable. These generally involve installing transportation tubes around the emergent ribbons, to support the ribbons.
U.S. Pat. Nos. 5,692,090 and 5,802,227 were granted Szegda and Dunn et al. respectively, for fiber optic cable end connectors. While these provided termination and support for the fiber cable, no provision was taught to support the individual fibers emerging from same, except one Szegda '090 embodiment taught support for a single central fiber ribbon.
U.S. Pat. Nos. 5,535,298, 6,510,273, 6,623,173 and 6,880,980 were granted Fasnacht et al, Ali et al, Grois et al., and Kang et al. respectively While these disclosed means to support fiber ribbons using transportation tubes, they suffered from the disadvantage of complexity, and therefore higher cost.